Combustion air directed into an internal combustion engine is generally directed through air cleaners before being directed into the engine compartment. In most climates, ambient air is a suitable source of combustion air. Therefore, air cleaners are generally manufactured with a perforated cap through which ambient air is received.
At extreme temperatures (for example, in extremely hot or cold climates), however, ambient air can be damaging to an internal combustion engine if used as combustion air. In addition, the ambient air source can become impeded or clogged by outside environmental conditions, such as snow, ice, and/or heavy dust conditions.
Therefore, there exists a need for switching the source of combustion air from ambient air to a conditioned air source, for example, warmed air delivered from the vehicle underhood area.